442 
PACIFIC SCIENCE, Vol. XI, October, 1957 
to 25 setae, patella with about 20 setae. Tibia 
of palp (Fig. 159) with a few sharp spines 
along the dorsal margin, 10 simple, smooth 
setae, plus the terminal clawlike seta and the 
heavy subterminal seta on the anterior aspect. 
Tarsus of palp with a solenidion at 0.50 p, a 
eupathid at 0.64*7 and four additional eupa- 
thids at or near the end of the segment, plus 
27 smooth setae. On the right palp of the 
specimen drawn there was a sharp spine at 
0.79*7, just anterior to the dorsal eupathid; on 
the left palp no such spine was found in this 
position, but one was found at 0.8^. Chaeto- 
taxy of legs essentially as described for male. 
male: Body 1,014-1,066 /i long, 520-598 
/x wide, length/width 1.78-1.95 (average of 
3 specimens 1,040 by 554 /jl, average length/ 
width, 1.88). Resembling female in all essen- 
tial respects except structure of genital area. 
Genital sclerites (Fig. 155) with 16 to 18 
setae in a single to double row, paragenital 
sclerites with 23-26 setae, also in a single to 
double row; an internal circlet of about 7 
pairs of setae. Genital acetabula numbering 
three pairs. Anal sclerites as described for 
female. 
Chaetotaxy of legs approximately as shown 
in table (s = solenidia, e = eupathidia, f = 
famulus, n = normal setae, m = many). 
All legs with telofemur to tarsus very rough 
in appearance (Figs. 162, 163). Solenidia ex- 
ceptionally well defined, with no intergrada- 
tion between types; s 3 slender, with no in- 
ternal structure, s 4 bacilliform with usually 
distinct internal structure, somewhat variable 
in length. Solenidiai and s 2 are not unlike s 3 
in general appearance, but differ principally 
in length and moreover occupy characteristic 
positions on the tarsi. Solenidia 4 absent from 
all but tarsus of leg I, but present on telo- 
femur to tarsus of legs II to IV. Vestigial 
setae absent from all legs. Tarsus I with 
famulus at 0.65*7, this seta resembling a eupa- 
thid but somewhat shorter. Solenidioni at 
0.80d, and three s 2 at 0.63, 0.76, and 0.87 p 
(Fig. 161). Tarsus II (Fig. 156) with spikelike 
famulus at 0.59*7, s 2 at 0.60*7, and a group of 
five s 4 at 0.18*7 to 0.49/. Tarsus II with only 
two eupathidia, one at 0.54/*7, the other at 
about 0.95 pv. Eupathidia present on all seg- 
ments of all legs beyond the basifemur, but 
few in number, rarely exceeding three except 
on tarsus I. Eupathidia of tarsus I extending 
from 0.35^ to 0.39*7. All tarsi with two slightly 
subequal claws and a rather small claw fossa. 
LARVA: Unknown. 
type locality: East fork of Hat Creek, 
above Hat Lake, at an elevation of about 
7,250 ft., Mount Lassen, California (holotype 
male), under rocks and sticks along the 
stream in a cascade meadow. August 7, 1955, 
collected by the writer. Type in author’s 
collection. 
The writer wishes to express his apprecia- 
tion to the National Park Service for their 
cooperation in these studies. As a general 
rule, most forms which can be collected 
within National Park boundaries can also be 
collected outside with nearly equal facility. 
However, three species of great interest in the 
present work (D. micidium , Johnstoniana latis- 
cuta , and Lassenia lasseni ) have been found 
only within the limits of Lassen Volcanic 
Park, despite intensive collecting at a large 
number of points in the Pacific coast states. 
remarks: This species can be readily dif- 
ferentiated from D. monoense n. sp. by several 
characteristics. It is much smaller, the length 
being about 1,040 \i compared with 1,630 to 
1,820 \i for D. monoense. There are about 20 
dorsal propodosomal setae outside of the 
scutum, compared with fewer than 10 in most 
tr 
bf 
tf 
pa 
ti 
ta 
n 
n 
S3 
s 4 
e 
S3 
s 4 
e 
S3 
s 4 
e 
Si 
s 2 
S3 
s 4 
e 
f 
I 
6 
m 
19 
0 
1 
53 
0 
2 
58 
0 
3 
1 
3 
0 
41 
m 
1 
II 
4,5 
m 
4 
1 
1 
10 
2 
1 
8 
3 
2 
0 
1 
0 
5 
2 
1 
III 
6 
m 
7 
1 
1 
13 
4 
2 
10 
3 
3 
0 
0 
0 
5 
2 
0 
IV 
14 
m 
7 
3 
1 
17 
6 
3 
16 
5 
3 
0 
0 
0 
5,6 
2,3 
0 
